//解析modbus报文
//Topic mq消息主题
//dConf 设备配置项
//dataBuf 报文
//callback 处理回调
async function mbPacketParse(topic,dConf,dataBuf,callback,chkRegNum=true)
{
  if(topic!='tx' && topic!='rx') return;//只接受tx和rx端点的数据
  if(dataBuf==null || dataBuf.length<5) return;//字节数太小，不符合modbus协议
  if(crc16_check(dataBuf,dConf.policy_id)==false) return;//modbus校验位

  const CFG = require('../config');
  const timLib = require('./time-lib');
  const rCache = require('../model/redis_cache');
  const PMR = require('../utils/policyManger');
  let isMainPkt = -1;//判断包类型

  if(!dConf.brother || dConf.brother==0)//单点采集
  {
    if(topic=='tx') isMainPkt=1;
    else if(topic=='rx') isMainPkt=0;
  }
  else if(dConf.brother==-1)//监听通信
  {
    if(topic=='rx'&&dataBuf.length==8) isMainPkt=1;
    else if(topic=='rx') isMainPkt=0;
  }
  else//透传通信
  {
    if(dConf.role=='slave'&&topic=='tx') isMainPkt=1;
    else if(dConf.role=='master'&&topic=='tx') isMainPkt=0;
  }

  if(isMainPkt==1)//主包处理
  {
    //modbus 主包分析
    let modObj={};
    modObj.addr=dataBuf[0];
    modObj.opt=dataBuf[1];
    if(modObj.opt==0x03)
    {
      modObj.regStart=dataBuf[2]*256+dataBuf[3];
      modObj.regNum=dataBuf[4]*256+dataBuf[5];
      modObj.stamp=timLib.NowStamp();
    }
    else if(modObj.opt==0x02)
    {
      modObj.regStart=dataBuf[2]*256+dataBuf[3];
      modObj.regNum=dataBuf[4]*256+dataBuf[5];
      modObj.stamp=timLib.NowStamp();
    }
    else if(modObj.opt==0x06)
    {
      modObj.func=(dataBuf[2]<<8)+dataBuf[3];
      modObj.num=(dataBuf[4]<<8)+dataBuf[5];
      modObj.code=(dataBuf[6]<<8)+dataBuf[7];
    }
    //console.log('master',modObj,timLib.NowStr());

    //存储到缓存，叠加policy_id，以支持设备采用2次同一策略
    rCache.set(PMR.rdNode(dConf),'last',modObj,CFG.MODBUS_RESP_GAP/1000);//2s自动过期
  }
  else if(isMainPkt==0)//回包处理
  {
    let stamp=timLib.NowStamp();
    let sConf;//从站配置

    if(topic=='rx') sConf=dConf;//主从一致
    else sConf=await rCache.getAll(rCache.N_Policy,dConf.brother);//获取从站配置,保持配置一致
    if(sConf==null) return;

    let last=await rCache.getAll(PMR.rdNode(sConf),'last');//获取设备配置
    if(last==null){console.log('[%d][%d] last is null',dConf.policy_id,dConf.hwid,PMR.rdNode(sConf));return;}

    if(stamp-last.stamp>CFG.MODBUS_RESP_GAP)//回包超时
    {console.log('[%d][%d]last timeout(%dmS)',dConf.policy_id,dConf.hwid,stamp-last.stamp);return;}

    //modbus数据分析
    let busAddr=dataBuf[0];//寄存器地址不对
    if(last.addr!=busAddr){console.log('[%d][%d] addr err, last%d, now%d',dConf.policy_id,dConf.hwid,last.addr,busAddr);return;}

    let busOpt=dataBuf[1];//操作码不对
    if(last.opt!=busOpt){console.log('[%d][%d] opt err',dConf.policy_id,dConf.hwid);return;}

    if(last.opt==0x03){
      let dataBytes=dataBuf[2];//寄存器数目不对
      let multi=dConf.data_width?dConf.data_width.split(':')[0]:2;
      if(chkRegNum==true && ((last.regNum*multi)&0xff)!=dataBytes){
        console.log('[%d][%d] regNum err, last %d now %d multi %d',dConf.policy_id,dConf.hwid,last.regNum,dataBytes,multi);
        return;
      }
    }
    else if(last.opt==0x02){ // 02功能码不验证
      last.regNum = dataBuf[2]/2;
// console.log('last11',last);
    }
    else if(last.opt==0x06)
    {
      let func=(dataBuf[2]<<8)+dataBuf[3];
      let num=(dataBuf[4]<<8)+dataBuf[5];
      let code=(dataBuf[6]<<8)+dataBuf[7];

      if(func!=last.func || num!=last.num  || code!=last.code){console.log('[%d][%d] regNum 06 err, last%d now%d',dConf.policy_id,dConf.hwid,last.code,code);return;}
    }
    //console.log('slave',slaveConf.hwid,data,timLib.NowStr());
    callback(last,sConf);
  }
}

//计算校验和
const _auchCRCHi = new Array(0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40);
const _auchCRCLo = new Array(0x00,0xC0,0xC1,0x01,0xC3,0x03,0x02,0xC2,0xC6,0x06,0x07,0xC7,0x05,0xC5,0xC4,0x04,0xCC,0x0C,0x0D,0xCD,0x0F,0xCF,0xCE,0x0E,0x0A,0xCA,0xCB,0x0B,0xC9,0x09,0x08,0xC8,0xD8,0x18,0x19,0xD9,0x1B,0xDB,0xDA,0x1A,0x1E,0xDE,0xDF,0x1F,0xDD,0x1D,0x1C,0xDC,0x14,0xD4,0xD5,0x15,0xD7,0x17,0x16,0xD6,0xD2,0x12,0x13,0xD3,0x11,0xD1,0xD0,0x10,0xF0,0x30,0x31,0xF1,0x33,0xF3,0xF2,0x32,0x36,0xF6,0xF7,0x37,0xF5,0x35,0x34,0xF4,0x3C,0xFC,0xFD,0x3D,0xFF,0x3F,0x3E,0xFE,0xFA,0x3A,0x3B,0xFB,0x39,0xF9,0xF8,0x38,0x28,0xE8,0xE9,0x29,0xEB,0x2B,0x2A,0xEA,0xEE,0x2E,0x2F,0xEF,0x2D,0xED,0xEC,0x2C,0xE4,0x24,0x25,0xE5,0x27,0xE7,0xE6,0x26,0x22,0xE2,0xE3,0x23,0xE1,0x21,0x20,0xE0,0xA0,0x60,0x61,0xA1,0x63,0xA3,0xA2,0x62,0x66,0xA6,0xA7,0x67,0xA5,0x65,0x64,0xA4,0x6C,0xAC,0xAD,0x6D,0xAF,0x6F,0x6E,0xAE,0xAA,0x6A,0x6B,0xAB,0x69,0xA9,0xA8,0x68,0x78,0xB8,0xB9,0x79,0xBB,0x7B,0x7A,0xBA,0xBE,0x7E,0x7F,0xBF,0x7D,0xBD,0xBC,0x7C,0xB4,0x74,0x75,0xB5,0x77,0xB7,0xB6,0x76,0x72,0xB2,0xB3,0x73,0xB1,0x71,0x70,0xB0,0x50,0x90,0x91,0x51,0x93,0x53,0x52,0x92,0x96,0x56,0x57,0x97,0x55,0x95,0x94,0x54,0x9C,0x5C,0x5D,0x9D,0x5F,0x9F,0x9E,0x5E,0x5A,0x9A,0x9B,0x5B,0x99,0x59,0x58,0x98,0x88,0x48,0x49,0x89,0x4B,0x8B,0x8A,0x4A,0x4E,0x8E,0x8F,0x4F,0x8D,0x4D,0x4C,0x8C,0x44,0x84,0x85,0x45,0x87,0x47,0x46,0x86,0x82,0x42,0x43,0x83,0x41,0x81,0x80,0x40);
function crc16(buffer,len=0)
{
  let crcHi=0xff;
  let crcLo=0xff;
  let i=0;

  if(len==0) len=buffer.length;

  for(i=0; i<len; i++)
  {
    let crcIndex = crcHi ^ buffer[i];
    crcHi = (crcLo ^ _auchCRCHi[crcIndex]);
    crcLo = _auchCRCLo[crcIndex];
  }

  return (crcHi<<8)+crcLo;
}

function crc16_check(buffer,id=0)
{
  let optCode=[0x02,0x03,0x06];//modbus操作码白名单
  let n=buffer.length;
  let crc=crc16(buffer,buffer.length-2);

  if(optCode.includes(buffer[1])==false)
  {
    console.log('[%d]modbus opt code[%d] err',id,buffer[1]);
    return false;
  }

  if(buffer[n-2]==(crc>>8) && buffer[n-1]==(crc&0xff)) return true;

  console.log('[%d]crc err',id,buffer.length,buffer[n-2]*256+buffer[n-1],crc);
  return false;
}


exports.mbPacketParse = mbPacketParse;
exports.crc16 = crc16;